package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.util.Collections;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private  static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    private BlockingQueue<VoucherOrder> orderTasks =  new ArrayBlockingQueue<>(1024*1024);

    private static final ExecutorService SECKILL_ORDER_EXCUTOR = Executors.newSingleThreadExecutor();

    //spring 初始化类就执行
    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXCUTOR.submit(new VocherOrderHandler());
    }

    //异步线程处理
    private class VocherOrderHandler implements Runnable {
        @Override
        public void run() {
            while (true) {
                try {
                    //1.获取队列中订单信息
                    VoucherOrder vouercherOrder = orderTasks.take();
                    //2.创建订单
                    handleVoucherOrder(vouercherOrder);
                } catch (Exception e) {
                    log.error("处理订单信息异常" , e);
                }
                //2.创建订单
            }
        }
    }

    private void handleVoucherOrder(VoucherOrder vouercherOrder) {
        //1.获取用户
        Long userId = vouercherOrder.getId();
        //intern返回字符串规范表示同一个地址
        //2.创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        boolean islock = lock.tryLock();
        //判断是否获取锁成功
        if(!islock){
            //获取锁失败,返回错误或重试
            log.error("不允许重复下单");
            return;
        }
        try {
            //拿到事务代理对象
            //创建接口调用
            proxy.createVoucher(vouercherOrder);
        } finally {
            //释放锁
            lock.unlock();
        }
    }

    private IVoucherOrderService proxy;

    @Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString()
        );
        //2.判断结果是否为0
        int r = result.intValue();
        if(result != 0){
            //2.1 不为0 没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //2.2为0 有购买资格,把下单信息保存到阻塞队列
        //2.3订单id
        long orderId = redisIdWorker.nextId("order");
        VoucherOrder voucherOrder = new VoucherOrder();
        voucherOrder.setId(orderId);
        //2.4用户id
        voucherOrder.setUserId(userId);
        //2.5代金卷id
        voucherOrder.setVoucherId(voucherId);
        //2.6存入阻塞队列
        orderTasks.add(voucherOrder);

       //3.获取代理对象(事务)
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //3.返回订单id
        return Result.ok(orderId);
    }

    /*@Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠卷
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            return Result.fail("秒杀尚未开始");
        }
        //3.判断秒杀是否结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            return Result.fail("秒杀已经结束");
        }
        //4.判断库存是否充足
        if (voucher.getStock() < 1) {
            //库存不足
            return Result.fail("库存不足");
        }
        Long UserId = UserHolder.getUser().getId();

        //intern返回字符串规范表示同一个地址
        //创建锁对象
        //SimpleRedisLock lock = new SimpleRedisLock(stringRedisTemplate, "order:" + UserId);
        RLock lock = redissonClient.getLock("lock:order:" + UserId);
        //获取锁
        boolean islock = lock.tryLock();
        //判断是否获取锁成功
        if(!islock){
            //获取锁失败,返回错误或重试
            return Result.fail("不允许重复下单");
        }
        try {
            //拿到事务代理对象
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            //创建接口调用
            return proxy.createVoucher(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }

    }*/


    @Transactional
    public void createVoucher(VoucherOrder voucherOrder){
            //一人一单
            Long UserId = voucherOrder.getUserId();
            //查询订单
            int count = query().eq("user_id", UserId).eq("voucher_id", voucherOrder.getVoucherId()).count();
            //判断是否存在
            if (count > 0) {
                log.error("用户已经购买过一次");
                return;
            }
            //5.扣减库存
            boolean success = seckillVoucherService.update().setSql("stock = stock - 1")
                    .eq("voucher_id", voucherOrder.getVoucherId())
                    .gt("stock", 0)
                    /*where id = and stock = (乐观锁)*/
                    .update();
            if (!success) {
                log.error("库存不足");
                return;
            }
            //6.创建订单
            save(voucherOrder);
    }
}
